Method and system for stacking printed circuit board

Abstract

A method and a system for stacking printed circuit boards includes providing a lower baseboard, a pinboard, and an upper baseboard; printing a first solder paste on the lower baseboard; placing a placement component on the lower baseboard; placing the pinboard on the lower baseboard; reflow soldering the lower baseboard with the placement component and the pinboard and forming a first assembly; printing the first solder paste and a second solder paste on the upper baseboard; placing the placement component on the upper baseboard and the first assembly on the upper baseboard; and reflow soldering the upper baseboard with the placement component and the first assembly and forming a printed circuit board; a melting point of the first solder paste is higher than a melting point of the second solder paste.

What is claimed is: 
     
       1. A method for stacking printed circuit boards comprising:
 providing a lower baseboard and printing a first solder paste on the lower baseboard; 
 placing a placement component on the lower baseboard; 
 providing a pinboard and placing the pinboard on the lower baseboard; 
 reflow soldering the lower baseboard with the placement component and the pinboard, to connect the placement component and the pinboard to the lower baseboard through the first solder paste, and thereby forming a first assembly; 
 providing an upper baseboard and printing the first solder paste and a second solder paste on the upper baseboard; 
 placing the placement component on the upper baseboard, and placing the first assembly on the upper baseboard; and 
 reflow soldering the upper baseboard with the placement component and the first assembly, to connect the placement component to the upper baseboard through the first solder paste, and to connect the first assembly to the upper baseboard through the second solder paste, and thereby forming a printed circuit board; 
 wherein a melting point of the first solder paste is higher than a melting point of the second solder paste. 
 
     
     
       2. The method according to  claim 1 , wherein the providing an upper baseboard and printing the first solder paste and a second solder paste on the upper baseboard comprises:
 providing the upper baseboard, the upper baseboard comprises an upper first surface and an upper second surface opposite to the upper first surface; 
 printing the first solder paste on the upper baseboard; and 
 printing the second solder paste on the upper first surface. 
 
     
     
       3. The method according to  claim 2 , wherein the printing the first solder paste on the upper baseboard comprises:
 printing the first solder paste on the upper second surface; and 
 printing the first solder paste on the upper first surface. 
 
     
     
       4. The method according to  claim 3 , wherein the printing the first solder paste on the upper first surface further comprises:
 arranging a first frame on the upper first surface; and printing the first solder paste on the upper first surface; 
 wherein the printing the second solder paste on the upper first surface further comprises: arranging a second frame on the upper first surface; and printing the second solder paste on the upper first surface; wherein the second frame is a stepped-shaped steel frame and configured to shelter the first solder paste. 
 
     
     
       5. The method according to  claim 4 , wherein the second frame comprises a print portion and a shelter portion, the print portion and the shelter portion form a stepped-shape, and the shelter portion is configured to shelter the printed first solder paste when printing the second solder paste. 
     
     
       6. The method according to  claim 5 , wherein the shelter portion comprises a supporter configured to resist against the upper baseboard. 
     
     
       7. The method according to  claim 1 , further comprising:
 after printing the solder paste on the upper baseboard and the lower baseboard, detecting whether any defect exists of the printing of the solder paste; wherein the solder paste comprises the first solder paste and the second solder paste; 
 after placing the placement component on the upper baseboard and the lower baseboard, detecting placing positions of the placement component; 
 
       after placing the pinboard on the lower baseboard, detecting a placing position of the pinboard; and
 after placing the first assembly on the upper baseboard, detecting a placing position of the first assembly. 
 
     
     
       8. A system for stacking printed circuit boards comprising:
 a solder paste printer configured to print a solder paste, the solder paste comprising a first solder paste and a second solder paste; 
 a pick and place machine configured to place components; and 
 a reflow soldering machine configured to perform reflow soldering; 
 wherein the solder paste printer is further configured to print the first solder paste on a lower baseboard, the pick and place machine is further configured to place a placement component and a pinboard on the lower baseboard, the reflow soldering machine is further configured to reflow solder the lower baseboard with the placement component and the pinboard, to connect the placement component and the pinboard to the lower baseboard through the first solder paste, and thereby forming a first assembly; 
 wherein the solder paste printer is further configured to print the second solder paste on a upper baseboard, the pick and place machine is further configured to place the placement component and the first assembly on the upper baseboard, the reflow soldering machine is further configured to reflow solder the upper baseboard with the placement component and the first assembly, to connect the placement component to the upper baseboard through the first solder paste, and to connect the first assembly to the upper baseboard through the second solder paste, and thereby forming a printed circuit board; and 
 wherein a melting point of the first solder paste is higher than a melting point of the second solder paste. 
 
     
     
       9. The system according to  claim 8 , wherein the upper baseboard comprises an upper first surface and an upper second surface opposite to the upper first surface; and the solder paste printer is further configured to print the first solder paste on the upper second surface and print the first solder paste on the upper first surface. 
     
     
       10. The system according to  claim 9 , wherein the solder paste printer is further configured to print the first solder paste on the upper second surface and print the first solder paste on the upper first surface. 
     
     
       11. The system according to  claim 10 , wherein the solder paste printer is further configured to arrange a first frame on the upper first surface and print the first solder paste on the upper first surface;
 the solder paste printer is further configured to arrange a second frame on the upper first surface and print the second solder paste on the upper first surface; and 
 wherein the second frame is a stepped-shaped steel frame and configured to shelter the first solder paste. 
 
     
     
       12. The system according to  claim 11 , wherein the second frame comprises a print portion and a shelter portion, the print portion and the shelter portion form a stepped-shape, and the shelter portion is configured to shelter the printed first solder paste when printing the second solder paste. 
     
     
       13. The system according to  claim 12 , the shelter portion comprises a supporter configured to resist against the upper baseboard. 
     
     
       14. The system according to  claim 8 , further comprising a solder paste detector configured to detect whether any defect exists of the printing of the solder paste, wherein the solder paste comprises the first solder paste and the second solder paste. 
     
     
       15. The system according to  claim 14 , further comprising a first optical appearance detector configured to detect the placing positions of the placement component, the pinboard, and the first assembly. 
     
     
       16. The system according to  claim 15 , further comprising a second optical appearance detector configured to detect whether any defect exists of the soldering of the placement component, the pinboard, and the first assembly.